Sewer and drainage · Exhaust path and connections
Locating leaking exhaust systems and undocumented connections in Vienna, Lower Austria and Burgenland
A leaking exhaust system rarely shows itself where it leaks: the generator runs, and exhaust gas stands in an area the system does not even pass through. A connection that appears in no plan behaves the same way – it ties in somewhere, and in the manhole nothing of it can be seen. Smoke testing answers both from outside: the sealed-off section is filled with visible smoke, and where the smoke comes back into the open lies the open spot. CFT locates, marks and records – repair is done by the client’s contractor. We serve Vienna, Lower Austria and Burgenland ourselves from Traiskirchen. Describe plant and suspicion on +43 (0) 2252 53169 or in writing to office@cft.at; sealing, access and date we then settle together.
What we do on site
We seal off the section concerned and charge it, then search surfaces, manholes and plant rooms for escapes. Every escape is marked, photographed and assigned to its run. If the section shows no escape, that is not proof of tightness.
Key facts at a glance
| Methods | Pipe smoke testing with visible smoke, tracer gas method, sealing off and feeding into the pipe network, combination with the camera survey |
|---|---|
| Application range | Exhaust systems of generators, sewer networks on industrial sites and in the public network |
| Duration | Two hours to one day, depending on the effort |
| Result format | Marked escapes at plant and network, photographic report per escape, assignment of undocumented connections to their line |
| Service area | Vienna, Lower Austria and Burgenland |
For you as a business
For municipalities, network operators and industrial plants this is not about comfort but about assignment: which connection goes into which sewer, where does an undocumented line tie in, where does exhaust gas leave its path. The method works non-invasively and, in extensive networks, tests the whole charged section at once instead of line by line. Two cases recur: the leaking exhaust system, usually at a generator, where the gas escapes at a spot where nobody suspects the system – and the connection that appears in no plan and whose path only the smoke reveals.
How the job runs
1. Scoping and coordination. We clarify the suspicion, the affected section, the access points and the operating hours, and define who is to be informed in advance. How well the smoke can be seen in the open also depends on weather and wind.
2. Preparing the section. We set the feed-in point and seal the test section off against the rest of the network. Water seals and siphons in the section must be filled, otherwise the smoke takes the short way out through the nearest floor drain.
3. Charging and walking. While the section stands under smoke, we walk areas, manholes, facades and plant rooms; whatever escapes is recorded on the spot. If nothing shows and the suspicion remains, the pass with tracer gas follows.
4. Assigning and handover. Every escape gets its on-site marking, its photograph and the line it belongs to. Nothing is closed, reconnected or repaired by us.
Equipment and methods
Pipe smoke testing with visible smoke
A fog generator fills the sealed-off section with visible smoke. The smoke takes every opening that is not closed and becomes visible exactly there: at the undocumented connection that appears in no plan, at the open pipe end, at the defective joint, at the crack. The method has two limits. Under a dense surface course the smoke migrates sideways and comes out next to the defect. And it only reaches what is air-filled: what lies below water level, in an inverted siphon or behind a filled water seal, stays invisible. A pass without an escape therefore says nothing about tightness.
Tracer gas method
Where the smoke yields nothing, a test gas goes into the section and is measured at the surface with the gas detector. This takes over when paving or screed lies above the pipe or when the escaping quantity is too small for visible smoke. It is paid for with time: the area is scanned lane by lane instead of being watched as a whole.
Sealing off and feeding in
Without sealing off, smoke or gas spreads through the whole network, and an escape no longer says which line delivers it – exactly the assignment this is about is lost. At the start therefore stand the boundary of the test section and the point where the feed goes in; in public networks this also determines which residents are to be informed beforehand. From the same definition follows which streets, yards and plant sections must be watched during the charging, and whether the emergency services get advance notice: smoke at a facade or out of a manhole cover is taken for a fire from outside.
Interplay with the camera survey
The two methods answer different questions. The camera drives the line and shows what is going on at the pipe – whether anything leaves to the outside at that spot stays open. The smoke shows the way out, but says nothing about the kind and condition of the spot. Only both together carry the decision whether to reconnect or to repair.
What you receive
Handed over are the markings on the object, the photographs of every escape and the assignment of escape to line. On this basis the client decides which connection is reconnected and which spot is repaired.
Costs and effort
There is no flat price. What a job costs follows from the extent of the network, the number of sections that must be charged separately, the accessibility of the manholes, the effort of coordinating with residents and emergency services, and whether tracer gas is used in addition. We name the cost range before the job.
Frequently asked questions
Can work continue during the smoke test?
The method is non-invasive, nothing is opened and nothing dug. Only what belongs to the sealed-off section is taken out of service; which plant parts those are, we define together before the date.
Who informs residents and emergency services?
Who informs whom is defined before the date. On public ground the notification is mandatory, not courtesy: escaping smoke gets reported, and a call-out binds more forces than a phone call beforehand.
Is a pass without an escape a proof of tightness?
No. The smoke only reaches air-filled sections; below water level, in the inverted siphon and behind filled siphons it shows nothing. Smoke testing answers the question of open paths and undocumented connections, not the question of tightness.
Smoke or tracer gas – when is which used?
One path can be seen, the other only measured. Over open areas, at facades and in manholes, smoke is faster, and everyone involved sees the escape themselves. If paving or screed lies above, or the quantity is small, the test gas with the detector remains – lane by lane instead of at a glance.
Related services
CCTV drainage survey
Once the opening is found and the condition of the pipe is to be assessed.
3D inspection in the works network
If it must first be established which branch leads to the escape.
Network locating and cable identification
If the undocumented connection found is to be followed to its origin.
Valve and hydrant caps
If the manhole through which the feed should go cannot be found at all.
Describe the findings.
The more precisely you describe the findings, the more directly we can go to work. Plans, readings and photos help us settle the method in advance.
What happens next
- We read your message and match the case to a method.
- We come back to you – usually with a question that shortens the appointment.
- We confirm the appointment and what it costs before anyone sets off.
Rather talk?
+43 (0) 2252 53169
Mon–Thu 8:00–16:30 · Fri 8:00–12:00
Describe your case.
Fastest by telephone – then we settle straight away which method fits and what you should prepare.
Outside office hours, write to office@cft.at.